Low latency visually lossless switching between different compression ratios

ABSTRACT

Systems and methods for low-delay video streaming featuring multiple video compression ratios. One embodiment of the system includes: a real-time video encoder (RT-VE) that receives an incoming high-definition uncompressed video (HD-UV), processes the incoming HD-UV according to first and second compression ratios, and sends the processed video over a resource reservation communication link to a real-time video decoder (RT-VD). The compression delay added by the RT-VE is below the duration of a single video frame, and the RT-VD converts the processed video into an outgoing HD-UV. Wherein on-the-fly switches between the first and second compression ratios, while continuing to receive the incoming HD-UV uninterruptedly, are both visually lossless switches and maintain a total delay between corresponding frames of the incoming HD-UV and the outgoing HD-UV that is below duration of two video frames.

BACKGROUND

Uncompressed and compressed video systems require differentcommunication rates, processors, and buffers. For example, anuncompressed Blu-Ray movie streamed with 1080p resolution (1920×1080pixels) requires a channel bandwidth of about 1.19 Gbps, versus just 25Mbps when compressed (using certain compression schemes). In anotherexample, 60 Hz uncompressed video frames with 1920×1080 pixels of 24bits typically require a channel bandwidth of about 3 Gbps.

Video resolution and frame rates that are typically used in consumerproducts have been increasing at a dramatic pace. For example, in recentyears, resolutions are transitioning from Standard Definition (480p) toHigh Definition (1080p) to Quad HD (2560×1440) to Ultra HD 4K(3840×2160), and frame rates are transitioning from 60 Hz to 120 Hz oreven to 240 Hz. In addition, there is demand for increased color bitprecision such as deep color that supports 30/36/48-bit values for threeRGB colors. These conditions place a heavy load on interfaces fortransferring uncompressed video data, such as High-Definition MultimediaInterface (HDMI).

Prior art systems cannot achieve visually lossless on-the-fly switchingbetween two light compression ratios at low delay, which is one of thefeatures of the disclosed embodiments.

BRIEF SUMMARY

In one embodiment, a low-delay video streaming system having multiplevideo compression ratios, includes: A real-time video encoder (RT-VE)configured to receive an incoming high-definition uncompressed video(HD-UV), process the incoming HD-UV according to at least one of firstand second compression ratios, and send the processed video over aresource reservation communication link to a real-time video decoder(RT-VD); wherein the first compression ratio is up to 5:1 and the secondcompression ratio is both deeper than the first compression ratio and upto 10:1; wherein compression delay added by the RT-VE is below durationof a single video frame for both compression ratios; the RT-VD isconfigured to convert the processed video into an outgoing HD-UV;wherein on-the-fly switches between the first and second compressionratios, while continuing to receive the incoming HD-UV uninterruptedly,are both visually lossless switches and maintain a total delay betweencorresponding frames of the incoming HD-UV and the outgoing HD-UV thatis below duration of two video frames.

In another embodiment, a method for low-delay video streaming havingmultiple video compression ratios, includes: Receiving, by a real-timevideo encoder (RT-VE), an incoming high-definition uncompressed video(HD-UV); converting the incoming HD-UV to a first compressed video,according to a first compression ratio of up to 5:1, while addingcompression delay below duration of a single video frame; sending thefirst compressed video to a real-time video decoder (RT-VD); converting,by the RT-VD, the first compressed video into an outgoing HD-UV; whilecontinuing to receive the incoming HD-UV uninterruptedly, switchingon-the-fly to converting the incoming HD-UV to a second compressedvideo, according to a second compression ratio of up to 10:1, whileadding compression delay below duration of a single video frame; whereinthe second compression ratio is deeper than the first compression ratio;sending the second compressed video to the RT-VD; and converting, by theRT-VD, the second compressed video into the outgoing HD-UV; wherein theswitching on-the-fly from the first compressed video to the secondcompressed video is a visually lossless switching that maintains a totaldelay, between corresponding frames of the incoming HD-UV and theoutgoing HD-UV, below duration of two video frames.

In still another embodiment, a low-delay communication system thatsupports visually lossless switches between different video compressionratios, includes: A real-time video encoder (RT-VE) configured toreceive an incoming high-definition uncompressed video (HD-UV), andcompress the incoming HD-UV into compressed video using: a firstintra-frame compression of ratio of up to 5:1, or a second intra-framecompression of ratio of up to 10:1, wherein the second intra-framecompression ratio is deeper than the first intra-frame compressionratio; and a real-time video decoder (RT-VD) configured to receive thecompressed video and decompress the compressed video into an outgoingHD-UV; wherein, while continuing to receive the incoming HD-UVuninterruptedly, the delay between corresponding video pixels of theincoming HD-UV and the outgoing HD-UV is below duration of two HD videoframes, and on-the-fly switches between the first and second compressionratios are visually lossless.

In one embodiment, a method for low-delay communication that supportsvisually lossless switches between different video compression ratios,includes: Receiving, by a real-time video encoder (RT-VE), an incominghigh-definition uncompressed video (HD-UV); compressing the incomingHD-UV into a first compressed video using a first intra-framecompression of ratio of up to 5:1, and sending it to a real-time videodecoder (RT-VD); decompressing, by the RT-VD, the first compressed videointo an outgoing HD-UV; while continuing to receive the incoming HD-UVuninterruptedly, switching on-the-fly to compressing the incoming HD-UVinto a second compressed video using a second intra-frame compression ofratio of up to 10:1, and sending it to the RT-VD; wherein the secondintra-frame compression ratio is deeper than the first intra-framecompression ratio; decompressing, by the RT-VD, the second compressedvideo into the outgoing HD-UV; wherein the switching on-the-fly is bothvisually lossless and maintains a total delay between correspondingvideo pixels of the incoming HD-UV and the outgoing HD-UV below durationof two HD video frames.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments are herein described, by way of example only, withreference to the accompanying drawings. In the drawings:

FIG. 1A illustrates one embodiment of a low-delay video streaming systemhaving multiple video compression ratios;

FIG. 1B illustrates a case where the total delay between correspondingframes is somewhat greater than one video frame;

FIG. 1C illustrates one embodiment of an encoder buffer able to storeless than two HD-UV frames;

FIG. 1D illustrates one embodiment of a decoder buffer able to storeless than two HD-UV frames;

FIG. 2 illustrates one embodiment of a method for low-delay videostreaming having multiple video compression ratios;

FIG. 3A illustrates one embodiment of a low-delay communication systemthat supports visually lossless switches between different videocompression ratios;

FIG. 3B illustrates a case where the total delay between correspondingframes is below the duration of a single video frame;

FIG. 4 illustrates one embodiment of a method for low-delaycommunication that supports visually lossless switches between differentvideo compression ratios;

FIG. 5A illustrates one embodiment of a fixed delay video communicationlink;

FIG. 5B illustrates a case where the total delay between correspondingframes is below the duration of a single video frame;

FIG. 5C illustrates one example of fast switching in which the secondcompression ratio is transmitted for a duration of one HD-UV frame untilswitching back to the first compression ratio;

FIG. 5D illustrates another example of fast switching in which thesecond compression ratio is transmitted for a duration that is shorterthan one HD-UV frame until switching back to the first compressionratio;

FIG. 6 illustrates one embodiment of a method for visually losslessvideo switching;

FIG. 7A illustrates one embodiment of a fixed delay video transmitterhaving multiple compression ratios;

FIG. 7B illustrates one embodiment of a method for switching betweendifferent compression ratios while maintaining a fixed delay;

FIG. 8A illustrates one embodiment of a compression system thatmaintains timing and primary colors while changing video compressionratios on-the-fly;

FIG. 8B illustrates one embodiment in which the outgoing HD-UV maintainsthe PRTUV;

FIG. 9 illustrates one embodiment of a method for maintaining timing andprimary colors while changing video compression ratios on-the-fly;

FIG. 10 illustrates one embodiment of a network that supports change tocompression ratios that is visually lossless to provide networkbandwidth for additional video streams;

FIG. 11 illustrates one embodiment of a method for visually losslesschanging of compression ratios to provide network bandwidth foradditional streams;

FIG. 12 illustrates one embodiment of a network that supports smoothswitching of video sources; and

FIG. 13 illustrates one embodiment of a method for smooth switching ofvideo sources.

DETAILED DESCRIPTION

FIG. 1A illustrates one embodiment of a low-delay video streaming systemhaving multiple video compression ratios. The low-delay video streamingsystem includes at least a real-time video encoder (RT-VE) 102 and areal-time video decoder (RT-VD) 104. The RT-VE 102 receives an incominghigh-definition uncompressed video (HD-UV) 101, processes the incomingHD-UV according to one of at least two compression ratios 106, and sendsthe processed video over a resource reservation communication link 103to the RT-VD 104. In one example, the compression ratios 106 include afirst compression ratio between 1:1 to 5:1 (referred to hereinafter as“up to 5:1”), and a second compression ratio that is up to 10:1; thedifference between the first and second compression ratios is at least25%. In some embodiments, the compression delay added by the RT-VE isbelow the duration of a single video frame for both compression ratios.

The RT-VD 104 converts the processed video into outgoing HD-UV 105. Thelow-delay video streaming system is characterized by the fact thaton-the-fly switches between the first and second compression ratios,while continuing to receive the incoming HD-UV uninterruptedly, arevisually lossless switches. The on-the-fly switches also maintain atotal delay, between corresponding frames of the incoming HD-UV and theoutgoing HD-UV, which is below the duration of two video frames. FIG. 1Billustrates a case where the total delay between corresponding frames ofthe incoming HD-UV 101 and the outgoing HD-UV 105 is somewhat greaterthan one video frame.

In one example, visually lossless switching indicates that a comparisonbetween corresponding frames of the incoming HD-UV and the outgoingHD-UV demonstrates that video synchronization signals and video timingsignals are undamaged as a result of the on-the-fly switches. In anotherexample, visually lossless switching indicates that a comparison betweencorresponding frames of the incoming HD-UV and the outgoing HD-UVdemonstrates that the on-the-fly switches between the first and secondcompression ratios do not result in one or more missing video frames. Instill another example, visually lossless switching indicates that acomparison between corresponding frames of the incoming HD-UV and theoutgoing HD-UV demonstrates that the on-the-fly switches between thefirst and second compression ratios do not result in one or more missingvideo frame lines. In still another example, visually lossless switchingindicates that a comparison between corresponding frames of the incomingHD-UV and the outgoing HD-UV demonstrates that the on-the-fly switchesbetween the first and second compression ratios do not result in one ormore missing video blanking signals. In still another example, visuallylossless switching indicates that no pixels are lost, excluding colordepth. And in still another example, visually lossless switchingindicates that a user watching the outgoing HD-UV is not expected toperceive an interruption in the HD video quality due to the switchesbetween the first and second compression ratios.

In one embodiment, the low-delay video streaming system further includesa controller 107 for setting the compression ratio of the system. Thecontroller may be implemented as part of at least one of the followingelements: the RT-VE, the RT-VD, and a network controller. In oneexample, the controller switches on-the-fly from the first compressionratio to the second compression ratio in order free up bandwidth for anew additional video stream.

In one embodiment, the low-delay video streaming system may feature asub-frame delay in which the total delay between corresponding frames ofthe incoming HD-UV 101 and the outgoing HD-UV 105 may be below theduration of a single video frame.

In one embodiment, the low-delay video streaming system features smoothcompression changes where the on-the-fly switches between the first andsecond compression ratios do not interrupt the flow of the uncompressedvideo from the decoder. Additionally or alternatively, the low-delayvideo streaming system may maintain a total delay that does not changewhen switching on-the-fly between the first and second compressionratios.

FIG. 1C illustrates one embodiment of an encoder buffer 110 able tostore less than two HD-UV frames. The encoder buffer 110 may beimplemented as part of the RT-VE 102, and stores the incoming HD-UV 101for the purpose of making the calculations required to compress theincoming HD-UV 101 into the compressed video. Optionally, the encoderbuffer 110 may be able to store less than one HD-UV frame, or even justa few HD-UV lines.

FIG. 1D illustrates one embodiment of a decoder buffer 120 able to storeless than two HD-UV frames. The decoder buffer 120 may be implemented aspart of the RT-VD 104, and stores the incoming processed video for thepurpose of making the calculations required to extract the outgoingHD-UV 105 from the processed video. Optionally, the decoder buffer 120may be able to store less than one outgoing HD-UV frame, or even just afew HD-UV lines.

FIG. 2 illustrates one embodiment of a method for low-delay videostreaming having multiple video compression ratios. The method includesthe following steps: In step 130, receiving, by a real-time videoencoder (RT-VE), an incoming high-definition uncompressed video (HD-UV).In step 131, converting the incoming HD-UV to a first compressed video,according to a first compression ratio of up to 5:1, while addingcompression delay below duration of a single video frame. In step 132,sending the first compressed video to a real-time video decoder (RT-VD).In step 133, converting, by the RT-VD, the first compressed video intoan outgoing HD-UV. In step 134, while continuing to receive the incomingHD-UV uninterruptedly, switching on-the-fly to converting the incomingHD-UV to a second compressed video, according to a second compressionratio of up to 10:1, while adding compression delay below duration of asingle video frame, wherein the second compression ratio is deeper thanthe first compression ratio. In step 135, sending the second compressedvideo to the RT-VD. And in step 136, converting, by the RT-VD, thesecond compressed video into the outgoing HD-UV, such that the switchingon-the-fly from the first compressed video to the second compressedvideo is a visually lossless switching that maintains a total delay,between corresponding frames of the incoming HD-UV and the outgoingHD-UV, below the duration of two video frames. Optionally, the switchingon-the-fly from the first compressed video to the second compressedvideo is done utilizing a controller that sets the compression ratio ofthe low-delay video streaming.

In one example, the switching on-the-fly between the first compressedvideo and the second compressed video does not change the total delaybetween corresponding frames of the incoming HD-UV and the outgoingHD-UV. In another example, the switching on-the-fly between the firstcompressed video to the second compressed video shifts the total delayin less than the duration of one video line.

In one example, the RT-VE used by the method may utilize a buffer ableto store less than two HD incoming uncompressed video frames in order tocompress the incoming HD-UV into the second compressed video.Additionally or alternatively, the RT-VD used by the method may utilizea buffer able to store less than one incoming HD lossless video frame inorder to extract the HD-UV from the first compressed video.

FIG. 3A illustrates one embodiment of a low-delay communication systemthat supports visually lossless switches between different videocompression ratios. The system includes at least a real-time videoencoder (RT-VE) 162 and a real-time video decoder (RT-VD) 164. The RT-VE162 receives an incoming high-definition uncompressed video (HD-UV) 161,and compresses the incoming HD-UV 161 into compressed video using eithera first intra-frame compression of ratio of up to 5:1 or a secondintra-frame compression of ratio of up to 10:1, wherein the differencebetween the first and second intra-frame compression ratios is at least25%. The RT-VD 164 receives the compressed video and decompresses thecompressed video into an outgoing HD-UV 165. In order to supportvisually lossless on-the-fly switches between the first and secondcompression ratios, the system maintains the delay between correspondingvideo pixels of the incoming HD-UV and the outgoing HD-UV below durationof two HD video frames, while continuing to receive the incoming HD-UVuninterruptedly.

In one example, using the on-the-fly visually lossless switchesindicates that the differences between the incoming HD-UV and theoutgoing HD-UV are visually lossless before, during, and after theswitches between the first and second compression ratios are performed.

In another example, the video compression is not intra-framecompression, and each of the first and second compression ratioscompresses at least 10 consecutive video frames between consecutiveon-the-fly ratio switches.

In still another example, the video compression is intra-framecompression. FIG. 3B illustrates a case where the total delay betweencorresponding frames of the incoming HD-UV 161 and the outgoing HD-UV165 is below the duration of a single video frame.

FIG. 4 illustrates one embodiment of a method for low-delaycommunication that supports visually lossless switches between differentvideo compression ratios. The method includes the following steps: Instep 180, receiving, by a real-time video encoder (RT-VE), an incominghigh-definition uncompressed video (HD-UV). In step 181, compressing theincoming HD-UV into a first compressed video using a first intra-framecompression of ratio of up to 5:1, and sending it to a real-time videodecoder (RT-VD). In step 182, decompressing, by the RT-VD, the firstcompressed video into outgoing HD-UV. In step 183, while continuing toreceive the incoming HD-UV uninterruptedly, switching on-the-fly tocompressing the incoming HD-UV into a second compressed video using asecond intra-frame compression of ratio of up to 10:1, and sending it tothe RT-VD, wherein the difference between the first and secondintra-frame compression ratios is at least 25%. And in step 184,decompressing, by the RT-VD, the second compressed video into theoutgoing HD-UV, wherein the switching on-the-fly is both visuallylossless and maintains a total delay between the corresponding videopixels of the incoming HD-UV and the outgoing HD-UV that is below theduration of two HD video frames.

Optionally, the method further includes the step of compressing at least10 consecutive video frames immediately before and after the switchingbetween different video compression ratios. Additionally oralternatively, the delay between the corresponding video pixels of theincoming HD-UV and the outgoing HD-UV is shorter than the duration of asingle video frame. Optionally, that short delay is also maintained whenswitching between different video compression ratios.

Visually lossless on-the-fly switching between compression ratios may beachieved using various mechanisms. In one embodiment, the videocommunication system includes a signaling mechanism that enables theencoder to notify the decoder about the switching between thecompression ratios. In one example, the encoder embeds the notificationin the packet header, and the decoder decodes the compressed dataaccording to the notification. In another example, the notification fromthe encoder to the decoder is placed in the compressed metadata, and thedecoder decodes the compressed data according to the metadata. In oneembodiment, the visually lossless switching between the compressionratios takes place on the border between the compression units when nohistory is saved in the decoder. In one example, switching betweenintra-frame compressions takes place on the border between first andsecond (subsequent) frames, such that the first compression ratio isused to compresses the first frame while the second compression ratio isused to compresses the second (subsequent) frame following the first. Inanother example, the decoder decodes each frame or set of framesindependently according to an indication about the compression used tocompress the data. Additionally, the encoder may not notify the decoderexplicitly about the switching between the compression ratios becausethe decoder is able to identify the change.

In another embodiment of a video system that achieves visually losslesson-the-fly switching between compression ratios, the encoder and decoderperform in parallel overlapping calculations at the time of switchingbetween the compression ratios. For example, assuming the compressionalgorithms operate on ten video lines, then in the vicinity of theswitching point, at least a portion of the ten video lines is processedin parallel by the two encoders and the two decoders (each pair of adecoder and encoder using one of the two corresponding compressionratios). Additionally, in this example, at least some overlappingcompressed data is sent over the communication link to the decoders inorder to achieve the visually lossless transition between the twocompression ratios. That is, data corresponding to at least a portion ofthe ten video lines is sent twice over the communication link, using thetwo different compression ratios.

In still another embodiment of a video system that achieves visuallylossless on-the-fly switching between compression ratios, time-sensitivevideo data is transmitted over a channel that also carriesnon-time-sensitive data, such as normal Ethernet data. Shortly prior tothe time of switching the compression ratios, the throughput of thenon-time-sensitive data is reduced to provide the extra bandwidth neededto carry the excess time-sensitive data required for the visuallylossless compression change, especially when time-sensitive data relatedto the two compression ratios is transmitted over the channelsimultaneously.

In still another embodiment of a video system that achieves visuallylossless on-the-fly switching between compression ratios, the systemutilizes dynamic waveform modulation communication scheme, such as theone described in U.S. Pat. No. 8,565,337, titled “Devices fortransmitting digital video and data over the same wires”, which isincorporated herein by reference in its entirety. The bandwidth used bythe dynamic waveform modulation communication system depends on channelproperties. When the interferences get below a threshold, less sensitivedata, such as video pixel data, is modulated using a higher modulationthat consumes less bandwidth. The spared bandwidth is then available tocarry the excess time-sensitive data required for the visually losslesscompression switching, such as sending two streams from two videosources or sending two streams using different compression ratios.Optionally, this embodiment further includes a controller that executesthe visually lossless switching when the interference conditions on thecommunication link are low enough to gain the spare bandwidth requiredfor the visually lossless switching.

In still another embodiment, the on-the-fly switching between thecompression ratios takes advantage of the fact that the viewer may beless sensitive to artifacts in the first (highest) and last (lowest)lines of the video frame, and in some cases the first and/or last linesmay not be displayed on the screen. These lines may be compressed by alossy compressor that generates observed artifacts, while the lines inbetween may be compressed by a lossless compressor.

FIG. 5A illustrates one embodiment of a fixed delay video communicationlink. The fixed delay video communication link includes at least areal-time video encoder (RT-VE) 202 and a real-time video decoder(RT-VD) 204. The RT-VE 202 receives an incoming high-definitionuncompressed video (HD-UV) 201, compresses the incoming HD-UV 201 intofirst or second HD compressed video, and transmits the HD compressedvideo over a communication link to the RT-VD 204. And the RT-VD 204decompresses the HD compressed video into the outgoing HD-UV 205. Thefixed delay video communication link is characterized by the fact thatwhile continuing to receive the incoming HD-UV uninterruptedly,on-the-fly switches between the first and second compression ratios areboth visually lossless and maintain the same fixed delay betweencorresponding pixels of the incoming HD-UV and the outgoing HD-UV. Inone embodiment, the fixed delay refers to accuracy shorter than theduration of a quarter of a HD-UV frame. In one embodiment, the firstcompression ratio of the first HD compressed video is between 1:1 and2:1, the second compression ratio of the second HD compressed video isup to 5:1, and the difference between the first and second compressionratios is at least 25%.

FIG. 5B illustrates a case where the total delay between correspondingframes of the incoming HD-UV 201 and the outgoing HD-UV 205 is below theduration of a single video frame, also in the vicinity of the transitionbetween the first compression ratio (1:1-2:1) and the second compressionratio (up to 5:1).

In order for the fixed delay video communication link to supporton-the-fly visually lossless switches between the first and secondcompression ratios, the steps of compressing the incoming HD-UV into thefirst or second HD compressed video and transmitting the HD compressedvideo over a communication link to the RT-VD may be interpretedaccording to one or more of the following three alternatives: (i)Compressing the incoming HD-UV into either the first or second HDcompressed video and transmitting either the first or second HDcompressed video over the communication link to the RT-VD, (ii)Compressing, at least for a short duration, the incoming HD-UV into boththe first and second HD compressed videos and transmitting either thefirst or second HD compressed video over the communication link to theRT-VD, and/or (iii) Compressing, at least for a short duration, theincoming HD-UV into both the first and second HD compressed videos, andtransmitting, for a duration shorter than 10 seconds, both the first andsecond HD compressed videos over the communication link to the RT-VD.

In one embodiment, at least some of the on-the-fly switches between thefirst and second compression ratios are performed gradually using athird compression ratio having value between the first and secondcompression ratios. The gradual switching is both visually lossless andmaintains the same fixed delay between corresponding pixels of theincoming HD-UV and the outgoing HD-UV. For example, a transition from2:1 compression to 4:1 compression may be performed gradually byswitching from 2:1 to 3:1, and then switching from 3:1 to 4:1.

In one embodiment, the first compression ratio is uncompressed video.Additionally or alternatively, the fixed delay video communication linkfurther includes a third HD compressed video having a third compressionratio up to 10:1, wherein the difference between the second and thirdcompression ratios is at least 25%, and on-the-fly switches between thesecond and third compression ratios, while continuing to receive theincoming HD-UV uninterruptedly, are both visually lossless and maintainthe same fixed delay between the corresponding pixels of the incomingHD-UV and the outgoing HD-UV.

In one embodiment, the first and second compressions are inter-framecompressions, and the video communication link further includes a buffer207 for storing video pixels in order to equalize the delays associatedwith the HD compressed video and the HD compressed video. The fixeddelay video communication link may further include a processor 208 forimplementing one or more of the described features. In still anotherembodiment, the first compression is an inter-frame compression, and thesecond compression is an intra-frame compression.

In one embodiment, the fixed delay video communication link supportsshort on-the-fly switches between the first and second compressionratios, such that the second compression ratio (e.g., 2:1-4:1) is usedto transmit data for a duration shorter than the duration required totransmit up to 3 HD-UV frames before switching back to the firstcompression ratio (e.g., 1:1-2:1). FIG. 5C illustrates one example offast switching in which the second compression ratio is used to transmitdata for a duration of one HD-UV frame before switching back to usingthe first compression ratio. FIG. 5D illustrates another example of fastswitching in which the second compression ratio is used to transmit datafor a duration that is shorter than one HD-UV frame before switchingback to using the first compression ratio.

Additionally or alternatively, the fixed delay video communication linkmay support short on-the-fly switches between the first and secondcompression ratios, such that the second compression ratio is used totransmit data for a duration shorter than the duration required totransmit 30 HD-UV frames before switching back to the first compressionratio.

In one example, visually lossless switching indicates that a comparisonbetween corresponding frames of the incoming HD-UV and the outgoingHD-UV demonstrates that video synchronization signals and video timingsignals are uninterrupted during the on-the-fly switches. In anotherexample, visually lossless switching indicates that a comparison betweencorresponding frames of the incoming HD-UV and the outgoing HD-UVdemonstrates that the on-the-fly switches between the first and secondcompression ratios do not result in one or more missing video frames. Instill another example, visually lossless switching indicates that acomparison between the corresponding frames of the incoming HD-UV andthe outgoing HD-UV demonstrates that the on-the-fly switches between thefirst and second compression ratios do not result in one or more missingvideo frame lines. In still another example, visually lossless switchingindicates that a comparison between corresponding frames of the incomingHD-UV and the outgoing HD-UV demonstrates that the on-the-fly switchesbetween the first and second compression ratios do not result in one ormore missing video blanking signals. In still another example, visuallylossless switching indicates that no pixels are lost, excluding colordepth.

FIG. 6 illustrates one embodiment of a method for visually losslessvideo switching. The method includes the following steps: In step 220,receiving an incoming high-definition uncompressed video (HD-UV). Instep 221, compressing, utilizing a processor, the incoming HD-UV into afirst HD compressed video having a first compression ratio between 1:1and 5:1. In step 222, transmitting the first HD compressed video over acommunication link to a real-time video decoder (RT-VD). In step 223,decompressing, by the RT-VD, the first HD compressed video into anoutgoing HD-UV. In step 224, compressing the incoming HD-UV into asecond HD compressed video having a second compression ratio between 2:1and 10:1, wherein the difference between the first and secondcompression ratios is at least 25%. In step 225, transmitting the secondHD compressed video over the communication link to the RT-VD. And instep 226, decompressing, by the RT-VD, the second HD compressed videointo an outgoing HD-UV. Optionally, on-the-fly switches between thefirst and second compression ratios, happening while continuing toreceive the incoming HD-UV uninterruptedly, are both visually losslessand maintain the same fixed delay between corresponding pixels of theincoming HD-UV and the outgoing HD-UV. In one example, the fixed delayrefers to accuracy shorter than the duration of a quarter of a HD-UVframe. In another example, the fixed delay refers to accuracy shorterthan the duration of one HD-UV frame. And in still another example, thefixed delay refers to accuracy shorter than the duration of one HD-UVpixel.

In one embodiment, the first compression ratio is uncompressed video.Additionally or alternatively, the method further includes a third HDcompressed video having a third compression ratio between 3:1 and 10:1,where the difference between the second and third compression ratios isat least 25%, and on-the-fly switches between the second and thirdcompression ratios, while continuing to receive the incoming HD-UVuninterruptedly, are both visually lossless and maintain the same fixeddelay between corresponding pixels of the incoming HD-UV and theoutgoing HD-UV.

In one embodiment, the method illustrated in FIG. 6 supports shorton-the-fly switches between the first and second compression ratios,such that the second compression ratio is used to transmit data for aduration of up to 3 HD-UV frames until switching back to using the firstcompression ratio. Additionally or alternatively, the method supportsshort on-the-fly switches between the first and second compressionratios, such that the second compression ratio is used to transmit datafor a duration shorter than the duration required to transmit 30 HD-UVframes before switching back to using the first compression ratio.

FIG. 7A illustrates one embodiment of a fixed delay video transmitterhaving multiple compression ratios. The fixed delay video transmitterincludes at least: a real-time video encoder (RT-VE) 242, a controller243, a buffer 244, and a transmitter 245. The RT-VE 242 receives anincoming high-definition uncompressed video (HD-UV) 241, and compressthe incoming HD-UV 241 into first or second light high-definition (HD)compressed videos. In one example, a first compression ratio of thefirst light HD compressed video is between 1:1 and 5:1, a secondcompression ratio of the second light HD compressed video is between 2:1and 5:1, and the difference between the first and second compressionratios is at least 25%.

The controller 243 includes buffer 244 for adjusting the delays of thefirst and second light HD compressed videos. The buffer may be locatedin at least one of the following places: before the RT-VE 242 (i.e., itstores data before it reaches the RT-VE 242), at the RT-VE 242, and/orafter the RT-VE 242 (i.e., it stores data that has left the RT-VE 242).The transmitter 245 sends the first or second light HD compressed videosover a communication link 246 after a fixed delay relative to theincoming HD-UV. In one example, the fixed delay refers to accuracyshorter than the duration of a quarter of a HD-UV frame.

In one embodiment, the fixed delay video transmitter maintains the samefixed delay for the first and second light HD compressed videos relativeto the incoming HD-UV while switching on-the-fly between the first andsecond compression ratios, and while continuing to receive the incomingHD-UV uninterruptedly. Optionally, the switching is visually lossless.

In one embodiment, in order to maintain the same fixed delay for thefirst and second light HD compressed videos relative to the incomingHD-UV, the controller 243 adds a longer delay to the first light HDcompressed video compared to the second light HD compressed video.

In one embodiment, the transmitter uses packets for sending the firstand second light HD compressed videos. The transmitter may use fixedsize packets and reduce the number of used packets as the compressionratio increases. Additionally or alternatively, the transmitter mayreduce the size of at least some of the packet payloads in order tomaintain a fixed packet rate with the different compression ratios. Inboth cases, the fixed delay may be calculated on average over a seriesof a few packets such that it is essentially unaffected by changes inthe packet size and/or packet rate. In one example, the fixed packetrate refers to inaccuracy of less than 1% in the rate over duration of aframe.

FIG. 7B illustrates one embodiment of a method for switching betweendifferent compression ratios while maintaining a fixed delay. The methodincludes the following steps: In step 260, receiving an incominghigh-definition uncompressed video (HD-UV). In step 261, compressing theincoming HD-UV into a first light high-definition (HD) compressed videohaving a first compression ratio of between 1:1 and 5:1. In step 262,sending the first light HD compressed video over a communication linkafter a first fixed delay relative to the incoming HD-UV. Optionally,the first fixed delay refers to accuracy shorter than the duration of aquarter of a HD-UV frame. In step 263, compressing the incoming HD-UVinto a second light HD compressed video having a second compressionratio of between 2:1 and 5:1, while continuing to receive the incomingHD-UV uninterruptedly. Optionally, the difference between the first andsecond compression ratios is at least 25%. And in step 264, sending thesecond light HD compressed video over the communication link after asecond fixed delay relative to the incoming HD-UV. Optionally, thesecond fixed delay refers to accuracy shorter than the duration of aquarter of a HD-UV frame.

In one embodiment, the difference between the first and second fixeddelays is less than 5% of the first fixed delay. The method may furtherinclude adding a longer delay to the first light HD compressed videocompared to the second light HD compressed video in order to equalizethe first and second fixed delays. Additionally or alternatively,switching between sending the first and second light HD compressedvideos does not result in damaging video synchronization signals andvideo timing signals of the incoming HD-UV. Additionally oralternatively, switching between sending the first and second light HDcompressed videos does not result in a missing frame line of theincoming HD-UV. Additionally or alternatively, switching between sendingthe first and second light HD compressed videos does not result in amissing blanking signal of the incoming HD-UV.

FIG. 8A illustrates one embodiment of a compression system thatmaintains timing and primary colors while changing video compressionratios on-the-fly. The compression system includes at least: a videotransmitter 282 and a video receiver 284. The video transmitter 282receives incoming high-definition uncompressed video (HD-UV) 280characterized by the following parameters related to uncompressed video(PRTUV): uncompressed timing requirements, uncompressed number of videolines, and uncompressed number of video pixels per video line. The videotransmitter 282 compresses the incoming HD-UV 280 into a firstcompressed video having a first compression ratio of between 1:1 and5:1, and sends the first compressed video over an outgoing compressedvideo link 283 to the video receiver 284. Upon receiving a command tosmoothly change on-the-fly the compression of the incoming HD-UV 280 toa second compressed video having a second compression ratio of between2:1 and 10:1, the video transmitter sends the second compressed videoover the outgoing compressed video link 283 to the video receiver 284,without interrupting the continuous flow of the incoming HD-UV. Thevideo receiver 284 decompresses the first and/or second compressedvideos to outgoing HD-UV. FIG. 8B illustrates one embodiment in whichthe outgoing HD-UV maintains the PRTUV before, during, and after thechange from the first compressed video to the second compressed video.Optionally, the outgoing HD-UV maintains also the primary colors of thepixels of the incoming HD-UV.

In one embodiment, the difference between the ratios of the first andsecond compressed videos is at least 25%. In one embodiment, the secondcompressed video is sent to the video receiver for a duration shorterthan the duration required to transmit 30 HD-UV frames, after which thevideo transmitter smoothly changes on-the-fly the compression of theincoming HD-UV to use the first compression ratio, and sends the firstcompressed video to the video receiver, without interrupting thecontinuous flow of the incoming HD-UV. Additionally or alternatively,the second compressed video may be sent to the video receiver for aduration of less than 3 HD-UV frames, after which the video transmittersmoothly changes on-the-fly the compression of the incoming HD-UV to usethe first compression, and sends the first compressed video to the videoreceiver, without interrupting the continuous flow of the incomingHD-UV.

In one embodiment, the first compressed video has compression ratiobetween 1:1 and 2:1, the second compressed video has compression ratiobetween 4:1 and 10:1, and the compression system further includes athird compressed video having a third compression ratio between 2:1 and4:1. Optionally, an on-the-fly change between the first and thirdcompressed videos maintains the PRTUV before, during, and after thechange. Additionally or alternatively, the on-the-fly change between thefirst and third compressed videos maintains also the primary colors ofthe pixels of the incoming HD-UV.

In one example, the primary colors are Red, Yellow and Blue (RYB), orRed, Green and Blue (RGB), and maintaining the primary colors requiresthat the difference between corresponding pixels of the incoming andoutgoing HD-UVs does not exceed a single shift on a 12 hue color wheel.In another example, the primary colors are Red, Yellow and Blue (RYB),or Red, Green and Blue (RGB), and in order to maintain the primarycolors the compression does not cause artifacts that replace one primarycolor with another primary color.

In one embodiment, compression techniques that maintain the primarycolors (Red, Yellow and Blue (RYB), or Red, Green and Blue (RGB)), inthe context of the disclosed embodiments, include compression techniquescausing artifacts that may affect the color depth and includecompression techniques causing artifacts that may result in a singleshift on a 12 hue color wheel, but exclude compression techniquescausing artifacts that replace one primary color with another primarycolor. For example, a compression technique that reduces color depth ofa pixel from 12 bits to 8 bits is considered herein a compressiontechnique that maintains the primary colors, while compression techniquethat derives a pixel value just from the values of the pixel'sneighbors, or duplicates a frame, are considered herein compressiontechniques that do not maintain the primary colors because a blue pixelmay easily be replaced by a red pixel when pixels are interpolated orduplicated instead of being transmitted.

In one embodiment, the outgoing HD-UV maintains a fixed delay relativeto the incoming HD-UV before, during, and after the change from thefirst compressed video to the second compressed video. Optionally, thefixed delay refers to accuracy shorter than the duration of a quarter ofa HD-UV frame.

In one embodiment, the compression system further includes a controller286 for issuing the command to smoothly change on-the-fly thecompression of the incoming HD-UV. The controller 286 may be implementedas part of at least one of the following elements: the videotransmitter, the video receiver, and/or a network controller.

Additionally or alternatively, the controller 286 may issue the commandto smoothly change on-the-fly the compression of the incoming HD-UV fromthe first compressed video, which is compressed at the first compressionratio, to the second compressed video, which is compressed at the secondcompression ratio. The command may be issued in order to: (i) free upbandwidth for a new additional video stream, and/or (ii) enable avisually lossless smooth change between the incoming HD-UV and a secondincoming HD-UV.

FIG. 9 illustrates one embodiment of a method for maintaining timing andprimary colors while changing video compression ratios on-the-fly. Themethod includes the following steps: In step 300, receiving, by a videotransmitter, incoming high-definition uncompressed video (HD-UV)characterized by the following parameters related to uncompressed video(PRTUV): uncompressed timing requirements, uncompressed number of videolines, and uncompressed number of video pixels per video line. In step301, compressing the incoming HD-UV into a first compressed video havinga first compression ratio of between 1:1 and 5:1. In step 302, sendingthe first compressed video over a communication link to a videoreceiver. In step 303, receiving, by the video transmitter, a command tosmoothly change on-the-fly the compression of the incoming HD-UV to asecond compressed video having a second compression ratio of between 2:1and 10:1. In step 304, sending the second compressed video over thecommunication link to the video receiver, without interrupting thecontinuous flow of the incoming HD-UV. Optionally, the differencebetween the ratios of the first and second compressed videos is at least25%. And in step 305, decompressing, by the video receiver, the firstand/or second compressed videos to an outgoing HD-UV, wherein theoutgoing HD-UV maintains the PRTUV before, during, and after the changefrom the first compressed video to the second compressed video.Optionally, the outgoing HD-UV maintains also the primary colors of thepixels of the incoming HD-UV.

In one embodiment, the method further includes sending the secondcompressed video to the video receiver during a duration shorter thanthe duration required to transmit 30 HD-UV frames, then smoothlychanging on-the-fly the compression of the incoming HD-UV to use thefirst compression ratio, and sending the first compressed video to thevideo receiver without interrupting the continuous flow of the incomingHD-UV. Additionally or alternatively, the method further includessending the second compressed video to the video receiver during aduration shorter than the duration required to transmit 3 HD-UV frames,then smoothly changing on-the-fly the compression of the incoming HD-UVto use the first compression ratio, and sending the first compressedvideo to the video receiver without interrupting the continuous flow ofthe incoming HD-UV.

In one embodiment of the method, the first compressed video hascompression ratio between 1:1 and 2:1, the second compressed video hascompression ratio between 4:1 and 10:1, and further comprising a thirdcompressed video having a third compression ratio between 2:1 and 4:1.The method further includes performing a smooth on-the-fly changebetween the first and third compressed videos while maintaining thePRTUV before, during, and after the smooth change.

In one embodiment, the method further includes maintaining fixed delaybetween the outgoing HD-UV and the incoming HD-UV before, during, andafter the change from the first compressed video to the secondcompressed video. Optionally, the fixed delay refers to accuracy shorterthan the duration of a quarter of a HD-UV frame.

In one embodiment, the method further includes performing the smoothchange on-the-fly in order to free up bandwidth for a new additionalvideo stream. Additionally or alternatively, the method further includesperforming the smooth change on-the-fly in order to enable a visuallylossless switching between the incoming HD-UV and a second incomingHD-UV.

FIG. 10 illustrates one embodiment of a network that supports change tocompression ratios that is visually lossless to provide networkbandwidth for additional video streams. The network includes at least afirst real-time video encoder (RT-VE) 330, a first network path (333,334, 335), a first real-time video decoder (RT-VD) 336, a second RT-VE340, a second network path (343, 334, 345), and a second RT-VD 346. Thefirst RT-VE 330 receives a first incoming high-definition uncompressedvideo (HD-UV), compresses the first incoming HD-UV into a firstcompressed video 332 using a first compression ratio of up to 10:1, andsends the first compressed video 332 over the first network path (333,334, 335) to the first RT-VD 336. The first RT-VD 336 extracts anoutgoing HD-UV from the first compressed video. Optionally, the outgoingHD-UV is visually lossless compared to the first incoming HD-UV.

After establishment of the first network path (333, 334, 335), and as aresult of insufficient bandwidth on the common link 334 included in thefirst network path, the second RT-VE 340 cannot send a second compressedvideo 342 to the second RT-VD 346 over the second network path (343,334, 345) that includes the common link 334. Optionally, the secondRT-VE 346 receives a second incoming HD-UV and compresses the secondincoming HD-UV into the second compressed video using a secondcompression ratio of up to 10:1. Therefore, in order to enable theadditional video stream, the first RT-VE increases on-the-fly the firstcompression ratio in proportion to the insufficient bandwidth and in amanner that is visually lossless for a human viewing the outgoing HD-UV.As a result of increasing on-the-fly of the first compression ratio, thesecond RT-VE can send the second compressed video to the second RT-VD,over the second network path, in parallel to the first compressed video.

In one embodiment, the network further includes a controller 350 forestimating the insufficient bandwidth, and then ordering the first RT-VE330 to increases on-the-fly the first compression ratio in proportion tothe insufficient bandwidth, and based on the estimated insufficientbandwidth. Optionally, the controller 350 is implemented as part of atleast one of the following elements: the RT-VE 330, the RT-VE 340, theRT-VD 336, the RT-VD 346, and/or a network controller. Additionally oralternatively, the network may be a resource reservation network.

In one example, the increasing on-the-fly of the first compression ratioin proportion to the insufficient bandwidth indicates that the increasereleases no more than 150% of the insufficient bandwidth, in relation tothe bandwidth used by the first compressed video before the increasingof the first compression ratio.

In one example, the first compression ratio, before increasing iton-the-fly, was between 1:1 and 5:1. In another example, the first andsecond compression ratios are between 1:1 and 5:1.

In one embodiment, the increasing on-the-fly of the first compressionratio maintains the same fixed delay between corresponding pixels of thefirst incoming HD-UV and the outgoing HD-UV. Optionally, the fixed delayrefers to accuracy shorter than the duration of a quarter of a HD-UVframe. Additionally or alternatively, the increasing on-the-fly of thefirst compression ratio maintains a total delay between correspondingframes of the first incoming HD-UV and the outgoing HD-UV that is belowthe duration of two video frames.

In one example, visually lossless increasing on-the-fly of the firstcompression indicates that a comparison between corresponding frames ofthe first incoming HD-UV and the outgoing HD-UV demonstrates that videosynchronization signals and video timing signals are uninterrupted as aresult of the increasing on-the-fly of the first compression ratio. Inanother example, visually lossless increasing on-the-fly of the firstcompression indicates that a comparison between corresponding frames ofthe first incoming HD-UV and the outgoing HD-UV demonstrates that theincreasing on-the-fly of the first compression ratio does not result inone or more missing video frames. In still another example, visuallylossless increasing on-the-fly of the first compression indicates that acomparison between corresponding frames of the first incoming HD-UV andthe outgoing HD-UV demonstrates that the increasing on-the-fly of thefirst compression ratio does not result in one or more missing videoblanking signals.

In one embodiment, the first RT-VE 330 comprises a buffer for storingthe first incoming HD-UV to make the calculations required to compressthe first incoming HD-UV into the first compressed video, and thecapacity of the buffer is below the capacity needed to store two videoframes of the first incoming HD-UV.

FIG. 11 illustrates one embodiment of a method for visually losslesschanging of compression ratios to provide network bandwidth foradditional streams. The method includes the following steps: In step360, receiving, by a first real-time video encoder (RT-VE), a firstincoming high-definition uncompressed video (HD-UV), compressing thefirst incoming HD-UV into a first compressed video using a firstcompression ratio of up to 10:1, and sending the first compressed videoover a first network path to a first real-time video decoder (RT-VD). Instep 361, extracting, by the first RT-VD, outgoing HD-UV from the firstcompressed video. Optionally, the outgoing HD-UV is visually losslesscompared to the first incoming HD-UV. In step 362, inferring that afterestablishing the first network path, and as a result of insufficientbandwidth on a common link included in the first network path, a secondRT-VE cannot send a second compressed video to a second RT-VD over asecond network path that includes the common link. Optionally, thesecond RT-VE receives a second incoming HD-UV and compresses the secondincoming HD-UV into the second compressed video using a secondcompression ratio of up to 10:1. And in step 363, increasing on-the-flythe first compression ratio in proportion to the insufficient bandwidth,in a manner that is visually lossless for a human viewing the outgoingHD-UV. As a result of increasing of the first compression ratio, thesecond RT-VE can send the second compressed video to the second RT-VD,over the second network path, in parallel to the first compressed video.

In one embodiment, the method further includes estimating theinsufficient bandwidth, and then ordering the first RT-VE to increaseson-the-fly the first compression ratio in proportion to the insufficientbandwidth, based on the estimated insufficient bandwidth.

In one example, the increasing on-the-fly of the first compression ratioin proportion to the insufficient bandwidth indicates that theincreasing releases no more than 150% of the insufficient bandwidth.Additionally or alternatively, the first and second compression ratiosmay be between 1:1 and 5:1.

In one embodiment, the increasing on-the-fly of the first compressionratio maintains the same fixed delay between corresponding pixels of thefirst incoming HD-UV and the outgoing HD-UV. Optionally, the fixed delayrefers to accuracy shorter than the duration of a quarter of a HD-UVframe. Additionally or alternatively, the increasing on-the-fly of thefirst compression ratio may maintain a total delay between correspondingframes of the first incoming HD-UV and the outgoing HD-UV that is belowthe duration of two video frames.

FIG. 12 illustrates one embodiment of a network that supports smoothswitching of video sources. The network includes at least a firstreal-time video encoder (RT-VE) 400, a first network path (403, 404,405), a first real-time video decoder (RT-VD) 406, a second RT-VE 410, asecond network path (413, 404, 415), a second RT-VD 416, a videoswitching controller 420, and a video switcher 422. The first RT-VEreceives a first incoming high-definition uncompressed video (HD-UV),compresses the first incoming HD-UV into a first compressed video 402using a first compression ratio of up to 5:1, and sends the firstcompressed video over the first network path (403, 404, 405) to thefirst RT-VD 406 that extracts a first outgoing HD-UV 407 from the firstcompressed video 402. The second RT-VE 410 receives a second incomingHD-UV, compresses the second incoming HD-UV into a second compressedvideo 412 using a second compression ratio of up to 5:1, and sends thesecond compressed video over the second network path (413, 404, 415) tothe second RT-VD 416 that extracts a second outgoing HD-UV 417 from thesecond compressed video 412.

The first and second network paths share a common link 404 havinginsufficient bandwidth to carry both the first and second compressedvideos (402, 412). In order to support smooth switching of videosources, the video switching controller 420 synchronizes the switchingbetween the first and second incoming HD-UVs by: indicating the firstRT-VE 400 and the second RT-VE 410 to increase the first and secondcompression ratios to ratios that enable the common link 404 to carryboth the first and second compressed videos (402, 412), indicating thevideo switcher 422 to perform a smooth switching between the first andsecond outgoing HD-UVs (407, 417), indicating the first RT-VE 400 tostop sending the first compressed video 402 after the smooth switching,and indicating the second RT-VE 410 to decrease the second compressionratio. Additionally, in order to enable the smooth switching, thetransients of the first and second outgoing HD-UV (407, 417), as aresult of increasing the first and second compression ratios, areperformed in a visually lossless manner compared to the first and secondincoming HD-UVs.

In one embodiment, the video switcher receives the first and secondoutgoing HD-UVs, performs the smooth switching, and outputs uncompressedvideo. In one example, the smooth switching between the first and secondoutgoing HD-UVs is a smooth switching without interruption during theswitching between the first and second outgoing HD-UVs.

In another embodiment, the video switcher receives the first and secondcompressed videos, performs the smooth switching, and outputsuncompressed video. In one example, the video switching controller isimplemented at the video switcher.

In one embodiment, the first and second incoming HD-UV are synchronized,and the video switcher does not perform video scaling. Alternatively,the first and second incoming HD-UV are unsynchronized, and the videoswitcher further performs video scaling. In one embodiment, the videoswitching controller is implemented as part of at least one of thefollowing devices: the first RT-VE, the second RT-VE, the videoswitcher, the first RT-VD, the second RT-VD, and a stand-alone device.

In one embodiment, the first RT-VE comprises at least two differentreal-time video encoders for different compression ratios. Additionallyor alternatively, the first RT-VE comprises a low compression real-timevideo encoder to compress the first compressed video before increasingthe first compression ratio, and a higher compression real-time videoencoder to compress the first compressed video after increasing thefirst compression ratio. In one example, the first compression ratio wasbetween 1:1 and 3:1 before increasing its compression ratio.

In one embodiment, the increasing of the first compression ratiomaintains the same fixed delay between corresponding pixels of the firstincoming HD-UV and the first outgoing HD-UV. Optionally, the fixed delayrefers to accuracy shorter than the duration of a quarter of a HD-UVframe. Additionally or alternatively, the increasing of the firstcompression ratio maintains a total delay between corresponding framesof the first incoming HD-UV and the first outgoing HD-UV that is belowthe duration of two video frames.

In one embodiment, the smooth switching is visually lossless for a humanviewing the HD-UV provided by the video switcher. In another embodiment,the smooth switching indicates that a comparison between the last fewcorresponding frames of the first compressed video and the firstoutgoing HD-UV until the smooth switching, and a comparison between thefirst few corresponding frames of the second compressed video and thesecond outgoing HD-UV immediately after the smooth switching,demonstrate that video synchronization signals and video timing signalsare uninterrupted as a result of the smooth switching. In still anotherembodiment, the smooth switching indicates that a comparison between thelast few corresponding frames of the first compressed video and thefirst outgoing HD-UV until the smooth switching, and a comparisonbetween the first few corresponding frames of the second compressedvideo and the second outgoing HD-UV immediately after the smoothswitching, demonstrate that the smooth switching does not result in oneor more missing video frames. In still another embodiment, the smoothswitching indicates that a comparison between the last few correspondingframes of the first compressed video and the first outgoing HD-UV untilthe smooth switching, and a comparison between the first fewcorresponding frames of the second compressed video and the secondoutgoing HD-UV immediately after the smooth switching, demonstrate thatthe smooth switching does not result in one or more missing videoblanking signals. And in still another embodiment, smooth switchingindicates that no pixels are lost, excluding color depth, as a result ofthe smooth switching.

FIG. 13 illustrates one embodiment of a method for smooth switching ofvideo sources. The method includes the following steps: In step 440,receiving, by a first real-time video encoder (RT-VE), a first incominghigh-definition uncompressed video (HD-UV), compressing the firstincoming HD-UV into a first compressed video using a first compressionratio of up to 5:1, and sending the first compressed video over a firstnetwork path to a first real-time video decoder (RT-VD). In step 441,extracting, by the first RT-VD, a first outgoing HD-UV from the firstcompressed video. In step 442, receiving, by a second RT-VE, a secondincoming HD-UV, compressing the second incoming HD-UV into a secondcompressed video using a second compression ratio of up to 5:1, andsending the second compressed video over a second network path to asecond RT-VD. In step 443, extracting, by the second RT-VD, a secondoutgoing HD-UV from the second compressed video. In step 444, inferringthat the first and second network paths share a common link havinginsufficient bandwidth to carry both the first and second compressedvideos. And synchronizing a smooth switching between the first andsecond outgoing HD-UVs using the following steps: In step 445,indicating the first RT-VE and the second RT-VE to increase the firstand second compression ratios to ratios that enable the common link tocarry both the first and second compressed videos. In step 446,indicating a video switcher to perform the smooth switching between thefirst and second outgoing HD-UVs. In step 447, indicating the firstRT-VE to stop sending the first compressed video after the smoothswitching. And in step 448, indicating the second RT-VE to decrease thesecond compression ratio.

In one embodiment, the smooth switching between the first and secondoutgoing HD-UVs is a smooth switching without interruption during theswitching between the first and second outgoing HD-UVs.

In one embodiment, the first and second incoming HD-UV areunsynchronized, and further comprising performing video scaling by thevideo switcher.

In one embodiment, the method further includes operating, by the firstRT-VE, a low compression real-time video encoder for compressing thefirst compressed video before increasing the first compression ratio,and operating a higher compression real-time video encoder to compressthe first compressed video after increasing the first compression ratio.In one example, the first compression ratio was between 1:1 and 3:1before increasing its compression ratio.

In one embodiment, the increasing of the first compression ratiomaintains the same fixed delay between corresponding pixels of the firstincoming HD-UV and the first outgoing HD-UV. Optionally, the fixed delayrefers to accuracy shorter than the duration of a quarter of a HD-UVframe. Additionally or alternatively, the increasing of the firstcompression ratio maintains a total delay between corresponding framesof the first incoming HD-UV and the first outgoing HD-UV that is belowduration of two video frames.

Herein, a predetermined value, such as a predetermined confidence levelor a predetermined threshold, is a fixed value and/or a value determinedany time before performing a calculation that compares a certain valuewith the predetermined value. A value is also considered to be apredetermined value when the logic, used to determine whether athreshold that utilizes the value is reached, is known before start ofperforming computations to determine whether the threshold is reached.

In this description, references to “one embodiment” mean that thefeature being referred to may be included in at least one embodiment ofthe invention. Moreover, separate references to “one embodiment” or“some embodiments” in this description do not necessarily refer to thesame embodiment. Additionally, references to “one embodiment” and“another embodiment” may not necessarily refer to different embodiments,but may be terms used, at times, to illustrate different aspects of anembodiment.

The embodiments of the invention may include any variety of combinationsand/or integrations of the features of the embodiments described herein.Although some embodiments may depict serial operations, the embodimentsmay perform certain operations in parallel and/or in different ordersfrom those depicted. Moreover, the use of repeated reference numeralsand/or letters in the text and/or drawings is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed. Theembodiments are not limited in their applications to the details of theorder or sequence of steps of operation of methods, or to details ofimplementation of devices, set in the description, drawings, orexamples. Moreover, individual blocks illustrated in the figures may befunctional in nature and therefore may not necessarily correspond todiscrete hardware elements.

While the methods disclosed herein have been described and shown withreference to particular steps performed in a particular order, it isunderstood that these steps may be combined, sub-divided, and/orreordered to form an equivalent method without departing from theteachings of the embodiments. Accordingly, unless specifically indicatedherein, the order and grouping of the steps is not a limitation of theembodiments. Furthermore, methods and mechanisms of the embodiments willsometimes be described in singular form for clarity. However, someembodiments may include multiple iterations of a method or multipleinstantiations of a mechanism unless noted otherwise. For example, whena processor is disclosed in one embodiment, the scope of the embodimentis intended to also cover the use of multiple processors. Certainfeatures of the embodiments, which may have been, for clarity, describedin the context of separate embodiments, may also be provided in variouscombinations in a single embodiment. Conversely, various features of theembodiments, which may have been, for brevity, described in the contextof a single embodiment, may also be provided separately or in anysuitable sub-combination. Embodiments described in conjunction withspecific examples are presented by way of example, and not limitation.Moreover, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art. It is to beunderstood that other embodiments may be utilized and structural changesmay be made without departing from the scope of the embodiments.Accordingly, this disclosure is intended to embrace all suchalternatives, modifications, and variations that fall within the spiritand scope of the appended claims and their equivalents.

What is claimed is:
 1. A low-delay video streaming system comprisingmultiple video compression ratios, comprising: a real-time video encoder(RT-VE) configured to receive an incoming high-definition uncompressedvideo (HD-UV), process the incoming HD-UV according to at least one offirst and second compression ratios, and send the processed video over aresource reservation communication link to a real-time video decoder(RT-VD); wherein the first compression ratio is up to 5:1 and the secondcompression ratio is both deeper than the first compression ratio and upto 10:1; wherein compression delay added by the RT-VE is below durationof a single video frame for both compression ratios; and the RT-VD isconfigured to convert the processed video into an outgoing HD-UV;wherein on-the-fly switches between the first and second compressionratios, by the RT-VD, while continuing to receive the incoming HD-UVuninterruptedly, are both visually lossless switches and maintain atotal delay between corresponding frames of the incoming HD-UV and theoutgoing HD-UV that is below duration of two video frames.
 2. Thelow-delay video streaming system of claim 1, wherein the visuallylossless switches indicate that a comparison between correspondingframes of the incoming HD-UV and the outgoing HD-UV demonstrates thatvideo synchronization signals and video timing signals are undamaged asa result of the on-the-fly switches.
 3. The low-delay video streamingsystem of claim 1, wherein the visually lossless switches indicate thata comparison between corresponding frames of the incoming HD-UV and theoutgoing HD-UV demonstrates that the on-the-fly switches between thefirst and second compression ratios do not result in a missing videoframe.
 4. The low-delay video streaming system of claim 1, wherein thevisually lossless switches indicate that a comparison betweencorresponding frames of the incoming HD-UV and the outgoing HD-UVdemonstrates that the on-the-fly switches between the first and secondcompression ratios do not result in a missing video frame line.
 5. Thelow-delay video streaming system of claim 1, wherein the visuallylossless switches indicate that a comparison between correspondingframes of the incoming HD-UV and the outgoing HD-UV demonstrates thatthe on-the-fly switches between the first and second compression ratiosdo not result in a missing video blanking signal.
 6. The low-delay videostreaming system of claim 1, wherein the visually lossless switchesindicate that no pixels are lost, excluding color depth.
 7. Thelow-delay video streaming system of claim 1, wherein the visuallylossless switches indicate that a user watching the outgoing HD-UV isnot expected to perceive an interruption in the HD video quality due tothe switches between the first and second compression ratios.
 8. Thelow-delay video streaming system of claim 1, further comprising acontroller configured to set the compression ratio of the low-delayvideo streaming system.
 9. The low-delay video streaming system of claim8, wherein the controller is implemented as part of at least one of thefollowing elements: the RT-VE, the RT-VD, and a network controller. 10.The low-delay video streaming system of claim 8, wherein the controlleris configured to switch on-the-fly from the first compression ratio tothe second compression ratio in order free up bandwidth for a newadditional video stream.
 11. The low-delay video streaming system ofclaim 1, wherein the total delay between corresponding frames of theincoming HD-UV and the outgoing HD-UV is below the duration of a singlevideo frame.
 12. The low-delay video streaming system of claim 1,wherein the on-the-fly switches between the first and second compressionratios do not interrupt the flow of the uncompressed video from thedecoder.
 13. The low-delay video streaming system of claim 1, whereinthe total delay does not change when switching on-the-fly between thefirst and second compression ratios.
 14. The low-delay video streamingsystem of claim 1, wherein the RT-VE comprises a buffer configured tostore the incoming HD-UV for the purpose of making the calculationsrequired to compress the incoming HD-UV into processed video, and thecapacity of the buffer is below the capacity needed to store two HD-UVframes.
 15. The low-delay video streaming system of claim 1, wherein theRT-VD comprises a buffer configured to store the incoming processedvideo for the purpose of making the calculations required to extract theoutgoing HD-UV from the processed video, and the capacity of the bufferis below the capacity needed to store two outgoing HD-UV frames.
 16. Amethod for low-delay video streaming comprising multiple videocompression ratios, comprising: receiving, by a real-time video encoder(RT-VE), an incoming high-definition uncompressed video (HD-UV);converting the incoming HD-UV to a first compressed video, according toa first compression ratio of up to 5:1, while adding compression delaybelow duration of a single video frame; sending the first compressedvideo to a real-time video decoder (RT-VD); converting, by the RT-VD,the first compressed video into an outgoing HD-UV; while continuing toreceive the incoming HD-UV uninterruptedly, switching on-the-fly toconverting the incoming HD-UV to a second compressed video, according toa second compression ratio of up to 10:1, while adding compression delaybelow duration of a single video frame; wherein the second compressionratio is deeper than the first compression ratio; sending the secondcompressed video to the RT-VD; and converting, by the RT-VD, the secondcompressed video into the outgoing HD-UV; wherein the switchingon-the-fly from the first compressed video to the second compressedvideo is a visually lossless switching that maintains a total delay,between corresponding frames of the incoming HD-UV and the outgoingHD-UV, below duration of two video frames.
 17. The method of claim 16,wherein the total delay does not change when switching on-the-flybetween the first compressed video and the second compressed video. 18.The method of claim 16, further comprising storing, by the RT-VE, lessthan two HD-UV frames in order to compress the incoming HD-UV into thesecond compressed video.
 19. The method of claim 16, further comprisingstoring, by the RT-VD, less than one compressed video frame in order toextract the outgoing HD-UV from the first compressed video.
 20. Alow-delay communication system that supports visually lossless switchesbetween different video compression ratios, comprising: a real-timevideo encoder (RT-VE) configured to receive an incoming high-definitionuncompressed video (HD-UV), and compress the incoming HD-UV intocompressed video using: a first intra-frame compression of ratio of upto 5:1, or a second intra-frame compression of ratio of up to 10:1,wherein the second intra-frame compression ratio is deeper than thefirst intra-frame compression ratio; and a real-time video decoder(RT-VD) configured to receive the compressed video and decompress thecompressed video into an outgoing HD-UV; wherein, while continuing toreceive the incoming HD-UV uninterruptedly, the delay betweencorresponding video pixels of the incoming HD-UV and the outgoing HD-UVis below duration of two HD video frames, and on-the-fly switchesbetween the first and second compression ratios are visually lossless.21. The low-delay communication system of claim 20, wherein theon-the-fly visually lossless switches indicate that the differencesbetween the incoming HD-UV and the outgoing HD-UV are visually losslessbefore, during, and after the switches between the first and secondcompression ratios are performed.
 22. The low-delay communication systemof claim 20, wherein each of the first and second compression ratioscompresses at least 10 consecutive video frames between consecutiveon-the-fly ratio switches.
 23. The low-delay communication system ofclaim 20, wherein the delay between the corresponding video pixels ofthe incoming HD-UV and the outgoing HD-UV is shorter than duration of asingle video frame.
 24. A method for low-delay communication thatsupports visually lossless switches between different video compressionratios, comprising: receiving, by a real-time video encoder (RT-VE), anincoming high-definition uncompressed video (HD-UV); compressing theincoming HD-UV into a first compressed video using a first intra-framecompression of ratio of up to 5:1, and sending it to a real-time videodecoder (RT-VD); decompressing, by the RT-VD, the first compressed videointo an outgoing HD-UV; while continuing to receive the incoming HD-UVuninterruptedly, switching on-the-fly to compressing the incoming HD-UVinto a second compressed video using a second intra-frame compression ofratio of up to 10:1, and sending it to the RT-VD; wherein the secondintra-frame compression ratio is deeper than the first intra-framecompression ratio; and decompressing, by the RT-VD, the secondcompressed video into the outgoing HD-UV; wherein the switchingon-the-fly is both visually lossless and maintains a total delay betweencorresponding video pixels of the incoming HD-UV and the outgoing HD-UVbelow duration of two HD video frames.
 25. The method of claim 24,further comprising compressing at least 10 consecutive video framesimmediately before and after the switching.
 26. The method of claim 24,wherein the delay between the corresponding video pixels of the incomingHD-UV and the outgoing HD-UV is shorter than duration of a single videoframe.